The need is felt in many devices, which in use provide an electronic controller, to introduce data through an input element.
Normally, an alphanumeric keyboard is provided; special pivoting keys also exist, which allow a limited number of multiple choices, typically four.
It is also well known the need of miniaturization of some electronic devices, such as mobile phones and “palm top” computers, as well as keyboards for dashboards, for example on a steering wheel.
Such miniaturization is often limited by the need to provide a keyboard whose size allows to operate easily the relative keys, owing to the typical size of the fingers of the hand. In these cases, keyboards are provided with a limited number of keys, giving to each key more functions, determined according to the push sequence of the keys same. Alternatively, sometimes, if possible, special actuating sticks are provided, which allow the discrimination of the characters even with a reduced size of the keyboard.
This last possibility, however, cannot be generalized, because the use of both hands is required, one for supporting the device and the other for operating the stick, and also because it is not advantageous in certain conditions for use in the outer environment.
In the following description reference is made to the fact that the invention can be applied for example as single key for operating cellular telephones, steering wheels for cars, etc.; such a reference should, however, be considered purely exemplifying and not limitative, since a skilled person is perfectly capable to design different uses all the times that it is necessary, or desirable, to provide an actuating means with a “single key of drive” for generating signals of different type, both for an end user and for any use in industrial fields.
It should be considered that an alphanumerical keyboard for computer has at least about 90 keys by which, if differently combined, it is possible to type at least about 200 alphanumerical characters or other symbols. Instead, in case of a mobile phone, where 15 keys are normally provided on average, for transmitting a much higher number of alphanumerical symbols, to the keys a “multiple” task is given. In other words, each key provides different signals depending on whether they are pressed only once or more times in quick succession. These keyboards are now very common, and their use is so common that mobile phone owners, in particular the youngest, do not have difficulty to type quickly even long messages (SMS).
Since the technology points toward miniaturization, the problem arises of a further reduction of size of an input system, replacing a keyboard, capable of generating a plurality of different signals in an easy and intuitive way.
Many types exist of devices adapted to solve, even if partially, the problems above described. For example, WO2004072837 describes an input device with a single key that can be operated in different directions within the range of action of a user's finger for the input of many controls. A plurality of sensor means is provided, to sense the approaching or the contact of the input key, and for generating a relative signal that is received by a control unit that finds out which sensor has been involved by the key and associates a corresponding command, which can be for example a letter of the alphabet, a number, etc. In this way the size of the input device can be remarkably reduced, allowing a miniaturization of the electronic apparatus that uses it. This device, however, provides a plurality of grooves arranged for example in the number of 12 each 360°. In each groove more sensors can be arranged. Then, the user chooses one of the twelve directions and pushes the key in that direction, passing all the sensors up to reaching that predetermined corresponding to the chosen character or command. This system can introduce input errors, since the user must stop at the sensor corresponding to the chosen command, and cannot go beyond it reaching the successive sensor, otherwise the chosen command is different.